This is what FN sent me for cleaning the matte wheels:
"I don't recommend using any wax designed for high gloss finishes They will make the wheels look glossy / streaky. Here are the products we used to clean and spray seal :
Chemical Guys - Meticulous Matte Auto Wash for Satin Finish & Matte Finish Paint (16 oz)
Chemical Guys - Meticulous Matte Detailer & Spray Sealant (16 oz)
I also recommend that you order high quality, edge-less micro fiber towels to apply the spray sealant/detailer.
You might see a product called Matte Jet Wax on the Chemical Guys website. I DO NOT recommend this product. We bought a bottle to test, and it turned our matte wheels shiny. In general the more you rub a matte clear coated finish the more likely you are to make it shiny. So while we do wax our high gloss wheels, we recommend that you only clean the wheels using the above products. There are some VERY expensive waxes on the market that claim to work well on matte finishes, but I haven't been able to sample them yet, so I cannot recommend them."